[ARM] 3855/1: Add generic time support

This patch adds Generic time-of-day support for the ARM architecture.

The support is currently added using #ifdef's so that it can support
sub-arches that do not (yet) have a clocksource added.  As sub-arches
add clocksource support, they should 'select GENERIC_TIME'
Signed-off-by: Deepak Saxena <dsaxena@mvista.com>
Signed-off-by: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Kevin Hilman <khilman@mvista.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

@@ -17,6 +17,10 @@ config ARM
 	  Europe.  There is an ARM Linux project with a web page at
 	  <http://www.arm.linux.org.uk/>.
 
+config GENERIC_TIME
+	bool
+	default n
+
 config MMU
 	bool
 	default y

arch/arm/kernel/time.c

@@ -69,10 +69,12 @@ EXPORT_SYMBOL(profile_pc);
  */
 int (*set_rtc)(void);
 
+#ifndef CONFIG_GENERIC_TIME
 static unsigned long dummy_gettimeoffset(void)
 {
 	return 0;
 }
+#endif
 
 /*
  * Scheduler clock - returns current time in nanosec units.
@@ -230,6 +232,7 @@ static inline void do_leds(void)
 #define	do_leds()
 #endif
 
+#ifndef CONFIG_GENERIC_TIME
 void do_gettimeofday(struct timeval *tv)
 {
 	unsigned long flags;
@@ -291,6 +294,7 @@ int do_settimeofday(struct timespec *tv)
 }
 
 EXPORT_SYMBOL(do_settimeofday);
+#endif /* !CONFIG_GENERIC_TIME */
 
 /**
  * save_time_delta - Save the offset between system time and RTC time
@@ -500,8 +504,10 @@ device_initcall(timer_init_sysfs);
 
 void __init time_init(void)
 {
+#ifndef CONFIG_GENERIC_TIME
 	if (system_timer->offset == NULL)
 		system_timer->offset = dummy_gettimeoffset;
+#endif
 	system_timer->init();
 
 #ifdef CONFIG_NO_IDLE_HZ

include/asm-arm/mach/time.h

@@ -38,7 +38,9 @@ struct sys_timer {
 	void			(*init)(void);
 	void			(*suspend)(void);
 	void			(*resume)(void);
+#ifndef CONFIG_GENERIC_TIME
 	unsigned long		(*offset)(void);
+#endif
 
 #ifdef CONFIG_NO_IDLE_HZ
 	struct dyn_tick_timer	*dyn_tick;

include/asm-arm/timeofday.h

+#ifndef _ASM_ARM_TIMEOFDAY_H
+#define _ASM_ARM_TIMEOFDAY_H
+#include <asm-generic/timeofday.h>
+#endif